From: Jeff Garzik <jgarzik@xxxxxxxxxxxxxxxx>
Date: Wed, 13 Feb 2002 03:33:41 -0500
When I boot into 2.2 MDK or custom kernel, SIOCGIFFLAGS indicates
IFF_PROMISC when tcpdump is running.
When I boot into 2.4 MDK or custom kernel, SIOCGIFFLAGS does not
indicate IFF_PROMISC under the same conditions.
Jeff, please, go into v2.2/linux/net/packet/af_packet.c and
read the comment above CONFIG_PACKET_MULTICAST and the code that
macro's definition controls.
In particular, read the commentary about multicast routing
daemons.
Something is different, perhaps your kernel is configured differently
or something else, but something is different as the code is
identical.